Incidences of pancreatic cancer and acute and chronic pancreatitis are rising globally, and often no curative treatment is available at the time of diagnosis. We tested the hypothesis that low and high plasma concentrations of pancreatic amylase are associated with increased risk of pancreatic cancer, acute pancreatitis, and chronic pancreatitis in the general population. We included 101,765 individuals (55% women) aged 20–100 years from the Copenhagen General Population Study with baseline measurements of plasma pancreatic amylase. After recruitment in 2004–2015 during a median 9 years of follow-up (range 0–15), we collected information about diagnoses of pancreatic cancer, acute pancreatitis, and chronic pancreatitis from the national Danish Patient Registry, the national Danish Cancer Registry, and the national Danish Causes of Death Registry. The median age was 58 years (interquartile range: 48–67) and the median plasma pancreatic amylase 32 U/L (26–40). During follow-up, 442 individuals were diagnosed with pancreatic cancer, 282 with chronic pancreatitis, and 401 with acute pancreatitis. Compared to individuals with pancreatic amylase levels in the 41st–60th percentiles, those with extreme low (1st–2.5th percentiles) and extreme high (97.5th–100th percentiles) pancreatic amylase had hazard ratios of 2.4 (95% confidence interval; 1.6–3.6) and 2.2 (1.4–3.7) for pancreatic cancer, of 1.8 (1.1–3.3) and 3.2 (1.8–5.6) for chronic pancreatitis, and of 1.1 (0.6–1.8) and 1.5 (0.8–2.7) for acute pancreatitis, respectively. In apparently healthy individuals from the general population, extreme low and extreme high plasma pancreatic amylase were associated with 2–threefold higher risk of both pancreatic cancer and chronic pancreatitis.